FIG. 10 is a main portion sectional view of an existing semiconductor module 500. FIG. 10 shows a state wherein the semiconductor module 500 is fixed to a metal cooler 62.
The existing semiconductor module 500 includes a metal base 51, an insulating substrate 54, a back surface metal plate 52 of which is fixed by solder 53 to the metal base 51, and a semiconductor chip 57 fixed by solder 56 to a front surface circuit plate 55 of the insulating substrate 54. Also, the existing semiconductor module 500 includes a resin case 58 fixed to the metal base 51, an external terminal 59 integrally molded with the case 58, the semiconductor chip 57, a circuit plate 55, and a wire 60 connected to the external terminal 59. Furthermore, the existing semiconductor module 500 includes a sealing material 61, such as gel, that fills the case 58. Further, the cooler 62 is fixed across a compound 63 with good thermal conductivity between the metal plate 52 and cooler 62.
FIG. 11 is a main portion sectional view of another existing semiconductor module 600.
Unlike the semiconductor module 500, the semiconductor module 600 includes the semiconductor chip 57 fixed by the solder 56 to the front surface circuit plate 55 of the insulating substrate 54, and an external terminal 65 (metal bar). Also, the semiconductor module 600 includes a leading end portion 65a of the bent external terminal 65, and a mold resin 66 that seals leaving a back surface 52a and one portion of a side surface 52b of the metal plate 52 exposed. The leading end portion 65a of the external terminal 65 is disposed above a nut globe 68, wherein a metal nut 67 is embedded in a depressed portion formed from the surface of the molded resin 66. The external terminal 65 and an unshown external wiring bar are fixed with a bolt, utilizing an unshown through hole formed in the leading end portion 65a of the external terminal 65, and the nut globe.
A single phase circuit, two phase circuit, or three phase circuit of an inverter circuit can be formed by the semiconductor module 500 or 600.
A gap is formed due to the effect of warping or the like between a back surface 51a of the metal base 51 and a flat surface 62a of the cooler 62 in the semiconductor modules 500 and 600. Therefore, a compound 63 with good fluidity is applied, or the compound 63 is applied thickly, in order that the compound 63 spreads throughout the interior of the gap. Further, by the compound 63 spreading easily, the adhesion between the metal base 51 and cooler 62 is increased.
Also, in PTL 1, a description is given of an electronics device wherein a semiconductor device and a cooler are fixed by metal nanoparticles.